The Lungs (Human Anatomy): Picture, Function, Definition, Conditions Human Anatomy Picture of the Lungs © 2014 WebMD, LLC. All rights reserved. The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). The trachea (windpipe) conducts inhaled air into the lungs through its tubular branches, called bronchi. The bronchi then divide into smaller and smaller branches (bronchioles), finally becoming microscopic. The bronchioles eventually end in clusters of microscopic air sacs called alveoli. In the alveoli, oxygen from the air is absorbed into the blood . Carbon dioxide , a waste product of metabolism , travels from the blood to the alveoli, where it can be exhaled. Between the alveoli is a thin layer of cells called the interstitium, which contains blood vessels and cells that help support the alveoli. The lungs are covered by a thin tissue layer called the pleura. The same kind of thin tissue lines the inside of the chest cavity -- also called pleura. A thin layer of fluid acts as a lubricant allowing the lungs to slip smoothly as they expand and contract with each breath.

Lung Conditions Chronic obstructive pulmonary disease ( COPD ): Damage to the lungs results in difficulty blowing air out, causing shortness of breath. Smoking is by far the most common cause of COPD. Emphysema : A form of COPD usually caused by smoking . The fragile walls between the lungs' air sacs (alveoli) are damaged, trapping air in the lungs and making breathing difficult. Chronic bronchitis : Repeated, frequent episodes of productive cough, usually caused by smoking . Breathing also becomes difficult in this form of COPD. Pneumonia : Infection in one or both lungs. Bacteria, especially Streptococcus pneumoniae, are the most common cause. Asthma : The lungs' airways (bronchi) become inflamed and can spasm, causing shortness of breath and wheezing . Allergies , viral infections , or air pollution often trigger asthma symptoms . Acute bronchitis : An infection of the lungs' large airways (bronchi), usually caused by a virus. Cough is the main symptom of acute bronchitis . Pulmonary fibrosis : A form of interstitial lung disease .

The interstitium (walls between air sacs) become scarred, making the lungs stiff and causing shortness of breath. Sarcoidosis : Tiny areas of inflammation can affect all organs in the body, with the lungs involved most of the time. The symptoms are usually mild; sarcoidosis is usually found when X-rays are done for other reasons. Obesity hypoventilation syndrome: Extra weight makes it difficult to expand the chest when breathing. This can lead to long-term breathing problems . Pleural effusion : Fluid builds up in the normally tiny space between the lung and the inside of the chest wall (the pleural space). If large, pleural effusions can cause problems with breathing. Pleurisy : Inflammation of the lining of the lung (pleura), which often causes pain when breathing in. Autoimmune conditions, infections, or a pulmonary embolism may cause pleurisy . Bronchiectasis: The airways (bronchi) become inflamed and expand abnormally, usually after repeated infections. Coughing , with large amounts of mucus, is the main symptom of bronchiectasis.

Lymphangioleiomyomatosis ( LAM ): A rare condition in which cysts form throughout the lungs, causing breathing problems similar to emphysema . LAM occurs almost exclusively in women of childbearing age. Cystic fibrosis : A genetic condition in which mucus does not clear easily from the airways. The excess mucus causes repeated episodes of bronchitis and pneumonia throughout life. Interstitial lung disease : A collection of conditions in which the interstitium (lining between the air sacs) becomes diseased. Fibrosis (scarring) of the interstitium eventually results, if the process can't be stopped. Lung cancer : Cancer may affect almost any part of the lung. Most lung cancer is caused by smoking . Respiratory System: Facts, Function and Diseases Respiratory System: Facts, Function and Diseases By Kim Ann Zimmermann, Live Science Contributor | March 11, 2016 05:55pm ET MORE The primary organs of the respiratory system are lungs, which function to take in oxygen and expel carbon dioxide as we breathe.

Credit: Leonello Calvetti | Shutterstock The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. The primary organs of the respiratory system are lungs, which carry out this exchange of gases as we breathe. Red blood cells collect the oxygen from the lungs and carry it to the parts of the body where it is needed, according to the American Lung Association . During the process, the red blood cells collect the carbon dioxide and transport it back to the lungs, where it leaves the body when we exhale. The human body needs oxygen to sustain itself. A decrease in oxygen is known as hypoxia and a complete lack of oxygen is known as anoxia and, according to MedLine Plus . These conditions can be fatal; after about four minutes without oxygen, brain cells begin dying, according to NYU Langone Medical Center , which can lead to brain damage and ultimately death. In humans, the average rate of breathing is dependent upon age. A newborn's normal breathing rate is about 40 times each minute and may slow to 20 to 40 times per minute when the baby is sleeping, according to the Children's Hospital of Philadelphia .

For adults, the average resting respiratory rate for adults is 12 to 16 breaths per minute, according to Johns Hopkins Medicine . Physical exertion also has an effect on respiratory rate, and healthy adults can average 45 breaths per minute during strenuous exercise. Parts of the respiratory system As we breathe, oxygen enters the nose or mouth and passes the sinuses, which are hollow spaces in the skull. Sinuses help regulate the temperature and humidity of the air we breathe. The trachea, also called the windpipe, filters the air that is inhaled, according to the American Lung Association. It branches into the bronchi, which are two tubes that carry air into each lung. The bronchial tubes are lined with tiny hairs called cilia. Cilia move back and forth, carrying mucus up and out. Mucus, a sticky fluid, collects dust, germs and other matter that has invaded the lungs. We expel mucus when we sneeze, cough, spit or swallow. The bronchial tubes lead to the lobes of the lungs. The right lung has three lobes; the left lung has two, according to the American Lung Association.

The left lung is smaller to allow room for the heart, according to the National Heart, Lung and Blood Institute (NHLBI). Lobes are filled with small, spongy sacs called alveoli, and this is where the exchange of oxygen and carbon dioxide occurs. The alveolar walls are extremely thin (about 0.2 micrometers). These walls are composed of a single layer of tissues called epithelial cells and tiny blood vessels called pulmonary capillaries. Blood passes through the capillaries. The pulmonary artery carries blood containing carbon dioxide to the air sacs, where the gas moves from the blood to the air, according to the NHLBI. Oxygenated blood goes to the heart through the pulmonary vein, and the heart pumps it throughout the body. The diaphragm, a dome-shaped muscle at the bottom of the lungs, controls breathing and separates the chest cavity from the abdominal cavity, the American Lung Association noted. When a breath it taken, it flattens out and pulls forward, making more space for the lungs. During exhalation, the diaphragm expands and forces air out.

Diseases of the respiratory system Diseases and conditions of the respiratory system fall into two categories: Viruses such as influenza, bacterial pneumonia and the new enterovirus respiratory virus that has been diagnosed in children; and chronic diseases, such as asthma and chronic obstructive pulmonary disease (COPD). According to Dr. Neal Chaisson, who practices pulmonary medicine at the Cleveland Clinic , there is not much that can be done for viral infections but to let them run their course. "Antibiotics are not effective in treating viruses and the best thing to do is just rest," he said. COPD is the intersection of three related conditions — chronic bronchitis, chronic asthma and emphysema, Chaisson told Live Science. It is a progressive disease that makes it increasingly difficult for sufferers to breath. Asthma is a chronic inflammation of the lung airways that causes coughing, wheezing, chest tightness or shortness of breath, according to Tonya Winders, president of the Allergy & Asthma Network .

These signs and symptoms may be worse when a person is exposed to their triggers, which can include air pollution, tobacco smoke, factory fumes, cleaning solvents, infections, pollens, foods, cold air, exercise, chemicals and medications. Lung cancer is often associated with smoking, but the disease can affect non-smokers as well. Every year, about 16,000 to 24,000 Americans die of lung cancer, even though they have never smoked, according to the American Cancer Society . Like all cancers, lung cancer is caused by the uncontrolled growth of abnormal cells. You use your eyes to see, your ears to hear and your muscles to do the heavy lifting. Well, sort of. In fact, most body parts are far more complicated than that, while some seem to have no business being inside there at all. Start Over | More Quizzes Diagnosing and treating respiratory ailments Pulmonologists, a subspecialty of internal medicine, treat the respiratory system, including the lungs, according to the American College of Physicians . Because of the critical nature of the respiratory system, pulmonologists work in hospitals as well as in private practice.

A pulmonologist must first be certified by the American Board of Internal Medicine and then obtain additional training in the subspecialty. Common diagnostic tools for diagnosing respiratory disease include chest X-rays and a pulmonary function test (PFT), according to Merck Manuals. A PFT measures how well the lungs take in and release air and how well they circulate oxygen. A doctor may also perform a bronchoscopy by inserting a tube with a light and camera into the airways — the trachea and the bronchial tubes — to examine for bleeding, tumors, inflammation or other abnormalities, according to the NHLBI. A similar procedure is a thoracoscopy, in which a doctor uses an optical device to examine the surfaces of the lungs. A physician may order a PFT as part of a routine exam — especially for smokers, according to the University of Pittsburgh Medical Center . A PFT may also be ordered to test lung function before surgery or to help diagnose lung conditions or diseases. For most healthy individuals, the most common respiratory ailment they may face is an infection, according to Dr. Matthew Exline, a pulmonologist and critical care expert at The Ohio State University Wexner Medical Center.

A cough is the first symptom, possibly accompanied by a fever. "However, cough can be a sign of chronic respiratory conditions such as asthma, chronic bronchitis or emphysema," he said. "In chronic lung disease, most respiratory diseases present with shortness of breath, initially with exertion, such as walking a significant distance or climbing several flights of stairs." The most certain way to diagnose asthma is with a lung function test, a medical history and a physical exam, according to Winders. "However, it's hard to do lung function tests in children younger than 5 years. Thus, doctors must rely on children's medical histories, signs and symptoms, and physical exams to make a diagnosis." For COPD, many patients benefit from respiratory rehabilitation, according to Dr. Brian Carlin, assistant professor of medicine at Drexel University College of Medicine . "It is much like cardiac rehabilitation for heart patients, and can provide education, exercise and training to reduce the number of respiratory incidents." Milestones Some milestones in the study of the respiratory system.

13th century: Anatomist and physiologist Ibn Al-Nafis advances his theory that the blood must have passed through the pulmonary artery, through the lungs, and back into the heart to be pumped around the body. This is believed by many to be the first scientific description of pulmonary circulation. 1897: Gustav Killian uses a rigid esophagoscope to extract a pork bone from a farmer's bronchus. 1898: A. Coolidge performs the first bronchoscopy in the United States at the Massachusetts General Hospital. 1905: Looking to improve the care of tuberculosis patients by sharing their experiences and discoveries, a small group of physicians form what becomes the American Thoracic Society. 1907: In Philadelphia, Chevalier Jackson develops and improves the instruments for bronchoscopy and esophagoscopy. 1963: James Hardy of the University of Mississippi performs the first human lung transplant. The patient lives for 18 days. 1964: Shigeto Ikeda develops a prototype of what was to be the first flexible bronchoscope. 1983: Joel D. Cooper, a thoracic surgeon, performs the first successful lung transplant in Toronto.

1986: Cooper performs the first successful double lung transplant. Find out all about your lungs and how breathing works. Credit: Ross Toro, Livescience contributor Editor’s Note: If you’d like more information on this topic, we recommend the following book: Human Lungs | Parts of Respiratory system | Human anatomy | 3D animation videos - YouTube Human Lungs | Parts of Respiratory system | Human anatomy | 3D animation videos Want to watch this again later? Sign in to add this video to a playlist. Need to report the video? Sign in to report inappropriate content. The interactive transcript could not be loaded. Loading... Rating is available when the video has been rented. This feature is not available right now. Please try again later. Published on Apr 24, 2013 Lungs - Part of Respiratory system | Human anatomy | 3D animation videos Humans for respiration need a continuous supply of oxygen. Humans take in oxygen and leave out carbon dioxide, which is the poisonous waste product in the process of respiration. The lungs are essential respiratory organs in the human body. The human anatomy consists of two lungs. They can be called as the left and the right lung, respectively.

The left lung has two lobes while the right lung has three lobes. The lungs contain approximately 1500 miles of airways and about 300 to 500 million alveoli. The total surface area is an approximate of 70m^2 (m-square) in a fully grown human body, (roughly the size of a badminton court). An alveoli , also known as "little cavity", is derived from the Latin word "alveolus", and these are the terminal ends of a respiratory tree and are shaped like a hollow-cavity. The average respiratory rates of a resting adult is about 10-20 breaths per minute. We spend about 1/3rd of a minute in inhaling. The total breathing capacity, however depends on the individual, that is, it varies on factors depending on age, height, weight and sex. It is observed that females tend to have a 20-25% lower breathing capacity than males, while tall people tend to have a larger lung capacity than shorter people.

And people living in low-lined areas, that is, at the sea-level, tend to have a smaller lung capacity than those people living at a higher altitude. People who smoke have a lower lung capacity than non-smokers. Lungs function similar to that of bellows, which is a mechanical device that blows strong current of air. **Lungs convert the hormones that cause the narrowing of blood vessels and drives the blood pressure up and also remove the waste products in the blood.** A lung is measured to be between 10-12 inches long. The two lungs are separated by a structure called "media sternum". The lungs are covered by a structure known as the "pulmonary pleura". The lung is an important organ that performs various functions that happen every second of our lives, out of which breathing is considered to be the most essential. As previously mentioned, the lungs take in oxygen and give out carbon dioxide. The air that we breathe in, enters the human body and reaches to the lungs through a windpipe , called trachea, which branches further into two main tubes which distributes the air supply to both the left and the right lung , respectively.

These tubes further divide themselves into 22 times the number of branches resulting in the formation of more than 100,000 smaller tubes, called bronchioles, and about 300 million air sacs( or alveoli), which are only about a 0.3 mm in diameter. Since the walls of the alveoli are 1/50th the thickness of a tissue paper and are also covered up with millions of tiny blood vessels, called capillaries, there is a free-flow exchange of both, oxygen and carbon dioxide, between the body and the environment. The lungs play an important role in the body's defense against infection and other harmful environmental factors. Air that is inhaled either through the nose or the mouth may consist of various dust particles or infectious agents, and ended up getting stored in the lungs. Mucus, which is a sticky liquid that is produced by the lungs, may trap the inhaled particles while the lung's white blood cells , that serve as protective agents, aid in the engulfment and destruction of such harmful matter and bacteria. Hence one good alternative is to cough. Coughing helps clear the mucus and other materials from the lungs.

Category Respiratory System | Interactive Anatomy Guide Female Full Respiratory System Description [Continued from above] . . . act as the functional units of the respiratory system by passing oxygen into the body and carbon dioxide out of the body. Finally, the muscles of respiration, including the diaphragm and intercostal muscles, work together to act as a pump, pushing air into and out of the lungs during breathing. Anatomy of the Respiratory System Nose and Nasal Cavity The nose and nasal cavity form the main external opening for the respiratory system and are the first section of the body’s airway—the respiratory tract through which air moves. The nose is a structure of the face made of cartilage, bone, muscle, and skin that supports and protects the anterior portion of the nasal cavity. The nasal cavity is a hollow space within the nose and skull that is lined with hairs and mucus membrane. The function of the nasal cavity is to warm, moisturize, and filter air entering the body before it reaches the lungs. Hairs and mucus lining the nasal cavity help to trap dust, mold, pollen and other environmental contaminants before they can reach the inner portions of the body.

Air exiting the body through the nose returns moisture and heat to the nasal cavity before being exhaled into the environment. Mouth The mouth, also known as the oral cavity , is the secondary external opening for the respiratory tract. Most normal breathing takes place through the nasal cavity, but the oral cavity can be used to supplement or replace the nasal cavity’s functions when needed. Because the pathway of air entering the body from the mouth is shorter than the pathway for air entering from the nose, the mouth does not warm and moisturize the air entering the lungs as well as the nose performs this function. The mouth also lacks the hairs and sticky mucus that filter air passing through the nasal cavity. The one advantage of breathing through the mouth is that its shorter distance and larger diameter allows more air to quickly enter the body. Pharynx The pharynx, also known as the throat, is a muscular funnel that extends from the posterior end of the nasal cavity to the superior end of the esophagus and larynx. The pharynx is divided into 3 regions: the nasopharynx, oropharynx, and laryngopharynx.

The nasopharynx is the superior region of the pharynx found in the posterior of the nasal cavity. Inhaled air from the nasal cavity passes into the nasopharynx and descends through the oropharynx, located in the posterior of the oral cavity. Air inhaled through the oral cavity enters the pharynx at the oropharynx . The inhaled air then descends into the laryngopharynx , where it is diverted into the opening of the larynx by the epiglottis. The epiglottis is a flap of elastic cartilage that acts as a switch between the trachea and the esophagus. Because the pharynx is also used to swallow food, the epiglottis ensures that air passes into the trachea by covering the opening to the esophagus. During the process of swallowing, the epiglottis moves to cover the trachea to ensure that food enters the esophagus and to prevent choking. Larynx The larynx , also known as the voice box, is a short section of the airway that connects the laryngopharynx and the trachea.

The larynx is located in the anterior portion of the neck, just inferior to the hyoid bone and superior to the trachea. Several cartilage structures make up the larynx and give it its structure. The epiglottis is one of the cartilage pieces of the larynx and serves as the cover of the larynx during swallowing. Inferior to the epiglottis is the thyroid cartilage , which is often referred to as the Adam’s apple as it is most commonly enlarged and visible in adult males. The thyroid holds open the anterior end of the larynx and protects the vocal folds. Inferior to the thyroid cartilage is the ring-shaped cricoid cartilage which holds the larynx open and supports its posterior end. In addition to cartilage, the larynx contains special structures known as vocal folds, which allow the body to produce the sounds of speech and singing. The vocal folds are folds of mucous membrane that vibrate to produce vocal sounds. The tension and vibration speed of the vocal folds can be changed to change the pitch that they produce.

Trachea The trachea, or windpipe, is a 5-inch long tube made of C-shaped hyaline cartilage rings lined with pseudostratified ciliated columnar epithelium. The trachea connects the larynx to the bronchi and allows air to pass through the neck and into the thorax. The rings of cartilage making up the trachea allow it to remain open to air at all times. The open end of the cartilage rings faces posteriorly toward the esophagus, allowing the esophagus to expand into the space occupied by the trachea to accommodate masses of food moving through the esophagus. The main function of the trachea is to provide a clear airway for air to enter and exit the lungs. In addition, the epithelium lining the trachea produces mucus that traps dust and other contaminants and prevents it from reaching the lungs. Cilia on the surface of the epithelial cells move the mucus superiorly toward the pharynx where it can be swallowed and digested in the gastrointestinal tract. Bronchi and Bronchioles At the inferior end of the trachea, the airway splits into left and right branches known as the primary bronchi.

The left and right bronchi run into each lung before branching off into smaller secondary bronchi. The secondary bronchi carry air into the lobes of the lungs—2 in the left lung and 3 in the right lung. The secondary bronchi in turn split into many smaller tertiary bronchi within each lobe. The tertiary bronchi split into many smaller bronchioles that spread throughout the lungs. Each bronchiole further splits into many smaller branches less than a millimeter in diameter called terminal bronchioles. Finally, the millions of tiny terminal bronchioles conduct air to the alveoli of the lungs. As the airway splits into the tree-like branches of the bronchi and bronchioles, the structure of the walls of the airway begins to change. The primary bronchi contain many C-shaped cartilage rings that firmly hold the airway open and give the bronchi a cross-sectional shape like a flattened circle or a letter D. As the bronchi branch into secondary and tertiary bronchi, the cartilage becomes more widely spaced and more smooth muscle and elastin protein is found in the walls. The bronchioles differ from the structure of the bronchi in that they do not contain any cartilage at all.

The presence of smooth muscles and elastin allow the smaller bronchi and bronchioles to be more flexible and contractile. The main function of the bronchi and bronchioles is to carry air from the trachea into the lungs. Smooth muscle tissue in their walls helps to regulate airflow into the lungs. When greater volumes of air are required by the body, such as during exercise, the smooth muscle relaxes to dilate the bronchi and bronchioles. The dilated airway provides less resistance to airflow and allows more air to pass into and out of the lungs. The smooth muscle fibers are able to contract during rest to prevent hyperventilation. The bronchi and bronchioles also use the mucus and cilia of their epithelial lining to trap and move dust and other contaminants away from the lungs. Lungs The lungs are a pair of large, spongy organs found in the thorax lateral to the heart and superior to the diaphragm. Each lung is surrounded by a pleural membrane that provides the lung with space to expand as well as a negative pressure space relative to the body’s exterior. The negative pressure allows the lungs to passively fill with air as they relax.

The left and right lungs are slightly different in size and shape due to the heart pointing to the left side of the body. The left lung is therefore slightly smaller than the right lung and is made up of 2 lobes while the right lung has 3 lobes. The interior of the lungs is made up of spongy tissues containing many capillaries and around 30 million tiny sacs known as alveoli . The alveoli are cup-shaped structures found at the end of the terminal bronchioles and surrounded by capillaries. The alveoli are lined with thin simple squamous epithelium that allows air entering the alveoli to exchange its gases with the blood passing through the capillaries. Muscles of Respiration Surrounding the lungs are sets of muscles that are able to cause air to be inhaled or exhaled from the lungs. The principal muscle of respiration in the human body is the diaphragm, a thin sheet of skeletal muscle that forms the floor of the thorax. When the diaphragm contracts, it moves inferiorly a few inches into the abdominal cavity, expanding the space within the thoracic cavity and pulling air into the lungs.

Relaxation of the diaphragm allows air to flow back out the lungs during exhalation. Between the ribs are many small intercostal muscles that assist the diaphragm with expanding and compressing the lungs. These muscles are divided into 2 groups: the internal intercostal muscles and the external intercostal muscles. The internal intercostal muscles are the deeper set of muscles and depress the ribs to compress the thoracic cavity and force air to be exhaled from the lungs. The external intercostals are found superficial to the internal intercostals and function to elevate the ribs, expanding the volume of the thoracic cavity and causing air to be inhaled into the lungs. Physiology of the Respiratory System Pulmonary Ventilation Pulmonary ventilation is the process of moving air into and out of the lungs to facilitate gas exchange. The respiratory system uses both a negative pressure system and the contraction of muscles to achieve pulmonary ventilation. The negative pressure system of the respiratory system involves the establishment of a negative pressure gradient between the alveoli and the external atmosphere. The pleural membrane seals the lungs and maintains the lungs at a pressure slightly below that of the atmosphere when the lungs are at rest.

This results in air following the pressure gradient and passively filling the lungs at rest. As the lungs fill with air, the pressure within the lungs rises until it matches the atmospheric pressure. At this point, more air can be inhaled by the contraction of the diaphragm and the external intercostal muscles, increasing the volume of the thorax and reducing the pressure of the lungs below that of the atmosphere again. To exhale air, the diaphragm and external intercostal muscles relax while the internal intercostal muscles contract to reduce the volume of the thorax and increase the pressure within the thoracic cavity. The pressure gradient is now reversed, resulting in the exhalation of air until the pressures inside the lungs and outside of the body are equal. At this point, the elastic nature of the lungs causes them to recoil back to their resting volume, restoring the negative pressure gradient present during inhalation. External Respiration External respiration is the exchange of gases between the air filling the alveoli and the blood in the capillaries surrounding the walls of the alveoli. Air entering the lungs from the atmosphere has a higher partial pressure of oxygen and a lower partial pressure of carbon dioxide than does the blood in the capillaries.

The difference in partial pressures causes the gases to diffuse passively along their pressure gradients from high to low pressure through the simple squamous epithelium lining of the alveoli. The net result of external respiration is the movement of oxygen from the air into the blood and the movement of carbon dioxide from the blood into the air. The oxygen can then be transported to the body’s tissues while carbon dioxide is released into the atmosphere during exhalation. Internal Respiration Internal respiration is the exchange of gases between the blood in capillaries and the tissues of the body. Capillary blood has a higher partial pressure of oxygen and a lower partial pressure of carbon dioxide than the tissues through which it passes. The difference in partial pressures leads to the diffusion of gases along their pressure gradients from high to low pressure through the endothelium lining of the capillaries. The net result of internal respiration is the diffusion of oxygen into the tissues and the diffusion of carbon dioxide into the blood. Transportation of Gases The 2 major respiratory gases, oxygen and carbon dioxide, are transported through the body in the blood. Blood plasma has the ability to transport some dissolved oxygen and carbon dioxide, but most of the gases transported in the blood are bonded to transport molecules.

Hemoglobin is an important transport molecule found in red blood cells that carries almost 99% of the oxygen in the blood. Hemoglobin can also carry a small amount of carbon dioxide from the tissues back to the lungs. However, the vast majority of carbon dioxide is carried in the plasma as bicarbonate ion. When the partial pressure of carbon dioxide is high in the tissues, the enzyme carbonic anhydrase catalyzes a reaction between carbon dioxide and water to form carbonic acid. Carbonic acid then dissociates into hydrogen ion and bicarbonate ion. When the partial pressure of carbon dioxide is low in the lungs, the reactions reverse and carbon dioxide is liberated into the lungs to be exhaled. Homeostatic Control of Respiration Under normal resting conditions, the body maintains a quiet breathing rate and depth called eupnea. Eupnea is maintained until the body’s demand for oxygen and production of carbon dioxide rises due to greater exertion. Autonomic chemoreceptors in the body monitor the partial pressures of oxygen and carbon dioxide in the blood and send signals to the respiratory center of the brain stem. The respiratory center then adjusts the rate and depth of breathing to return the blood to its normal levels of gas partial pressures.

Prepared by Tim Taylor, Anatomy and Physiology Instructor Human Respiratory System and Lungs; How They Work Clearing the Air You usually don't even notice it, but twelve to twenty times per minute, day after day, you breathe -- thanks to your body's respiratory system . Your lungs expand and contract, supplying life-sustaining oxygen to your body and removing from it, a waste product called carbon dioxide . The Act of Breathing Breathing starts at the nose and mouth . You inhale air into your nose or mouth , and it travels down the back of your throat and into your windpipe, or trachea . Your trachea then divides into air passages called bronchial tubes. For your lungs to perform their best, these airways need to be open during inhalation and exhalation and free from inflammation or swelling and excess or abnormal amounts of mucus. As the bronchial tubes pass through the lungs, they divide into smaller air passages called bronchioles. The bronchioles end in tiny balloon-like air sacs called alveoli. Your body has over 300 million alveoli. The alveoli are surrounded by a mesh of tiny blood vessels called capillaries.

Here, oxygen from the inhaled air passes through the alveoli walls and into the blood . After absorbing oxygen, the blood leaves the lungs and is carried to your heart . Your heart then pumps it through your body to provide oxygen to the cells of your tissues and organs. As the cells use the oxygen, carbon dioxide is produced and absorbed into the blood. Your blood then carries the carbon dioxide back to your lungs, where it is removed from the body when you exhale. The Diaphragm's Role in Breathing Inhalation and exhalation are the processes by which the body brings in oxygen and expels carbon dioxide. The breathing process is aided by a large dome-shaped muscle under the lungs called the diaphragm. When you breathe in, the diaphragm contracts downward, creating a vacuum that causes a rush of fresh air into the lungs. The opposite occurs with exhalation, where the diaphragm relaxes upwards, pushing on the lungs, allowing them to deflate. Clearing the Air The respiratory system has built-in methods to prevent harmful substances in the air from entering the lungs. Hairs in your nose help filter out large particles.

Microscopic hairs, called cilia, are found along your air passages and move in a sweeping motion to keep the air passages clean. But if harmful substances, such as cigarette smoke, are inhaled, the cilia stop functioning properly, causing health problems like bronchitis . Mucus produced by cells in the trachea and bronchial tubes keeps air passages moist and aids in stopping dust, bacteria and viruses, allergy -causing substances, and other substances from entering the lungs. Impurities that do reach the deeper parts of the lungs can often be moved up via mucous and coughed out or swallowed. WebMD Medical Reference Circulatory System: Facts, Function & Diseases Circulatory System: Facts, Function & Diseases By Kim Ann Zimmermann, Live Science Contributor | March 11, 2016 05:30pm ET MORE The circulatory system is a vast network of organs and vessels that is responsible for the flow of blood, nutrients, hormones, oxygen and other gases to and from cells. Without the circulatory system, the body would not be able to fight disease or maintain a stable internal environment — such as proper temperature and pH — known as homeostasis.

Description of the circulatory system While many view the circulatory system, also known as the cardiovascular system, as simply a highway for blood, it is made up of three independent systems that work together: the heart (cardiovascular); lungs (pulmonary); and arteries, veins, coronary and portal vessels (systemic), according to the U.S National Library of Medicine (NLM). In the average human, about 2,000 gallons (7,572 liters) of blood travel daily through about 60,000 miles (96,560 kilometers) of blood vessels, according to the Arkansas Heart Hospital . An average adult has 5 to 6 quarts (4.7 to 5.6 liters) of blood, which is made up of plasma, red blood cells, white blood cells and platelets. In addition to blood, the circulatory system moves lymph, which is a clear fluid that helps rid the body of unwanted material. The heart, blood, and blood vessels make up the cardiovascular component of the circulatory system. It includes the pulmonary circulation, a "loop" through the lungs where blood is oxygenated.

It also incorporates the systemic circulation, which runs through the rest of the body to provide oxygenated blood, according to NLM. [ Top 10 Amazing Facts About Your Heart ] The pulmonary circulatory system sends oxygen-depleted blood away from the heart through the pulmonary artery to the lungs and returns oxygenated blood to the heart through the pulmonary veins, according to the Mayo Clinic . Oxygen-deprived blood enters the right atrium of the heart and flows through the tricuspid valve (right atrioventricular valve) into the right ventricle. From there it is pumped through the pulmonary semilunar valve into the pulmonary artery on its way to the lungs. When it gets to the lungs, carbon dioxide is released from the blood and oxygen is absorbed. The pulmonary vein sends the oxygen-rich blood back to the heart, according to NLM. The systemic circulation is the portion of the circulatory system is the network of veins, arteries and blood vessels that transports blood from heart, services the body's cells and then re-enters the heart, the Mayo Clinic noted. Diseases of the circulatory system According to the American Heart Association , cardiovascular disease is the leading cause of death in the United States.

Because of its vastness and critical nature, it is one of the systems of the body most prone to disease. One of the most common diseases of the circulatory system is arteriosclerosis, in which the fatty deposits in the arteries causes the walls to stiffen and thicken the walls. According to the Mayo Clinic, the causes are a buildup of fat, cholesterol and other material in the artery walls. This can restrict blood flow or in severe cases stop it all together, resulting in a heart attack or stroke. Stroke involves blockage of the blood vessels to the brain and is another major condition of the circulatory system, according to Mitchell Weinberg of the North Shore-LIJ Health System . “Risk factors include smoking, diabetes and high cholesterol,” he noted. Another circulatory disease, hypertension — commonly called high blood pressure — causes the heart to work harder and can lead to such complications as a heart attack, a stroke, or kidney failure, the NLM noted. An aortic aneurysm occurs when the aorta is damaged and starts to bulge or eventually tear, which can cause severe internal bleeding.

This weakness can be present at birth or the result of atherosclerosis, obesity, high blood pressure or a combination of these conditions, according to Weinberg. Peripheral arterial disease (also known as PAD) typically involves areas of narrowing or blockage within an artery, according to Jay Radhakrishnan , an interventional radiologist in Houston, Texas. In addition, chronic venous insufficiency (also known as CVI) involves areas reflux (or backward flow) within the superficial veins of the lower extremities. PAD is diagnosed with noninvasive testing including ultrasound, CT scan, and/or MRI. Ultrasound is the least expensive of these methods, but also gives the least amount of detail, as CT and MRI show a much higher degree of anatomic detail when identifying areas of narrowing/blockage within an artery. CVI is diagnosed with ultrasound as the venous reflux can be measured accurately by ultrasound, which ultimately guides treatment. Study of the circulatory system Cardiologists are specialists who are certified to diagnose, treat and prevent disease of the heart, arteries and veins. Cardiologists are certified by the American Board of Internal Medicine (ABIM) after meeting educational and practice requirements.

Before being certified as cardiologists, those aspiring to the specialty must be certified in internal medicine. Then cardiologists can become certified in one of several cardiology subspecialties, including transplant cardiology, cardiovascular disease, clinical cardiac electrophysiology and interventional cardiology. You use your eyes to see, your ears to hear and your muscles to do the heavy lifting. Well, sort of. In fact, most body parts are far more complicated than that, while some seem to have no business being inside there at all. Milestones Some milestones in the history and study of the circulatory system include: 16th century B.C.: The Ebers Papyrus, an ancient Egyptian medical document, provides some of the earliest writing on the circulatory. It describes the connection of the heart to the arteries. 6th century B.C.: Ayurvedic physician Sushruta in ancient India describes how vital fluids circulate through the body. 2nd century A.D.: the Greek physician Galen documents how blood vessels carry blood, identifies venous (dark red) and arterial (brighter and thinner) blood and notes that each has a separate functions. 1628: William Harvey, an English physician, first describes blood circulation.

1706: Raymond de Vieussens, a French anatomy professor, first describes the structure of the heart's chambers and vessels. 1733: Stephen Hales, an English clergyman and scientist, measures blood pressure for the first time. 1816: Rene T.H. Laennec, a French physician, invents the stethoscope. 1902: American physician James B. Herrick first documents heart disease resulting from hardening of the arteries. 1903: Dutch physiologist Willem Einthoven invents the electrocardiograph. 1952: The first successful open heart surgery takes place by F. John Lewis, an American surgeon. 1967: South African surgeon Christiaan Barnard performs the first transplant of a whole heart from one person to another. 1982: American physician Robert Jarvik designs the first artificial heart and American surgeon Willem DeVries implants it. Editor's Note: If you'd like more information on this topic, we recommend the following book, available on Amazon.com: Lungs, Lungs Information, Breathing Facts, News, Photos -- National Geographic This requires the latest version of Flash Player. Click here to download.

Our lungs fuel us with oxygen, the body's life-sustaining gas. They breathe in air, then extract the oxygen and pass it into the bloodstream, where it's rushed off to the tissues and organs that require it to function. Oxygen drives the process of respiration, which provides our cells with energy. The waste gas carbon dioxide is produced as a byproduct and disposed of when we exhale. Without this vital exchange our cells would quickly die and leave the body to suffocate. Since the lungs process air, they are the only internal organs that are constantly exposed to the external environment. Central to the human respiratory system, they breathe in between 2,100 and 2,400 gallons (8,000 and 9,000 liters) of air each day—the amount needed to oxygenate the 2,400 gallons (9,000 liters) or so of blood that is pumped through the heart daily. Intricate Construction Our two lungs are made up of a complex latticework of tubes, which are suspended, on either side of the heart, inside the chest cavity on a framework of elastic fibers.

Air is drawn in via the mouth and the nose, the latter acting as an air filter by trapping dust particles on its hairs. The air is warmed up before passing down the windpipe, where it's divided at the bottom between two airways called bronchi that lead to either lung. Within the lungs, the mucus-lined bronchi split like the branches of a tree into tens of thousands of ever smaller tubes (bronchioles), which connect to tiny sacs called alveoli. The average adult's lungs contain about 600 million of these spongy, air-filled structures. There are enough alveoli in just one lung to cover an area roughly the size of a tennis court. The alveoli are where the crucial gas exchange takes place. The air sacs are surrounded by a dense network of minute blood vessels, or capillaries, which connect to the heart. Those that link to the pulmonary arteries carry deoxygenated blood that needs to be refreshed. Oxygen passes through the incredibly thin walls of the alveoli into the capillaries and is then carried back to the heart via the pulmonary veins. At the same time, carbon dioxide is removed from the blood through the same process of diffusion.

This waste gas is expelled as we breathe out. The rate at which we breathe is controlled by the brain, which is quick to sense changes in gas concentrations. This is certainly in the brain's interests—it's the body's biggest user of oxygen and the first organ to suffer if there's a shortage. In and Out The actual job of breathing is done mainly by the diaphragm, the sheet of muscles between the chest and abdomen. These muscles contract when we breathe in, expanding the lungs and drawing in air. We breathe out simply by relaxing the diaphragm; the lungs deflate like balloons. Lungs are delicate organs and vulnerable to a range of illnesses. The most common of these in Western countries are bronchitis and emphysema, which are often caused by smoking. Tubes inside the lung become chronically inflamed, producing excess mucus. Smoking can also lead to lung cancer, the world's major cancer, which is diagnosed in 1.4 million people a year. Circulatory System: Pulmonary and Systemic Circuits Circulatory System: Pulmonary and Systemic Circuits Sign Up for Our Free Newsletters Thanks, You're in! Health Tip of the Day Recipe of the Day There was an error.

Please try again. Please select a newsletter. Please enter a valid email address. Did you mean ? Your Lungs & Respiratory System Your Lungs & Respiratory System What's something that you do all day, every day, no matter where you are or who you're with? (a) think about what's for lunch tomorrow (b) put your finger in your nose (c) hum your favorite song (d) breathe It's possible that some kids could say (a) or (c) or that others might even say — yikes! — (b). But every single person in the world has to say (d). Breathing air is necessary for keeping humans (and many animals) alive. And the two parts that are large and in charge when it comes to breathing? If you guessed your lungs, you're right! Your lungs make up one of the largest organs in your body, and they work with your respiratory system to allow you to take in fresh air, get rid of stale air, and even talk. Let's take a tour of the lungs! Locate Those Lungs Your lungs are in your chest, and they are so large that they take up most of the space in there.

You have two lungs, but they aren't the same size the way your eyes or nostrils are. Instead, the lung on the left side of your body is a bit smaller than the lung on the right. This extra space on the left leaves room for your heart. Your lungs are protected by your rib cage, which is made up of 12 sets of ribs. These ribs are connected to your spine in your back and go around your lungs to keep them safe. Beneath the lungs is the diaphragm (say: DY-uh-fram), a dome-shaped muscle that works with your lungs to allow you to inhale (breathe in) and exhale (breathe out) air. You can't see your lungs, but it's easy to feel them in action: Put your hands on your chest and breathe in very deeply. You will feel your chest getting slightly bigger. Now breathe out the air, and feel your chest return to its regular size. You've just felt the power of your lungs! continue A Look Inside the Lungs From the outside, lungs are pink and a bit squishy, like a sponge. But the inside contains the real lowdown on the lungs!

At the bottom of the trachea (say: TRAY-kee-uh), or windpipe, there are two large tubes. These tubes are called the main stem bronchi (say: BRONG-kye), and one heads left into the left lung, while the other heads right into the right lung. Each main stem bronchus (say: BRONG-kuss) — the name for just one of the bronchi — then branches off into tubes, or bronchi, that get smaller and even smaller still, like branches on a big tree. The tiniest tubes are called bronchioles (say: BRONG-kee-oles), and there are about 30,000 of them in each lung. Each bronchiole is about the same thickness as a hair. At the end of each bronchiole is a special area that leads into clumps of teeny tiny air sacs called alveoli (say: al-VEE-oh-lie). There are about 600 million alveoli in your lungs and if you stretched them out, they would cover an entire tennis court. Now that's a load of alveoli!

Each alveolus (say: al-VEE-oh-luss) — what we call just one of the alveoli — has a mesh-like covering of very small blood vessels called capillaries (say: CAP-ill-er-ees). These capillaries are so tiny that the cells in your blood need to line up single file just to march through them. All About Inhaling When you're walking your dog, cleaning your room, or spiking a volleyball, you probably don't think about inhaling (breathing in) — you've got other things on your mind! But every time you inhale air, dozens of body parts work together to help get that air in there without you ever thinking about it. As you breathe in, your diaphragm contracts and flattens out. This allows it to move down, so your lungs have more room to grow larger as they fill up with air. "Move over, diaphragm, I'm filling up!" is what your lungs would say. And the diaphragm isn't the only part that gives your lungs the room they need. Your rib muscles also lift the ribs up and outward to give the lungs more space.

At the same time, you inhale air through your mouth and nose, and the air heads down your trachea, or windpipe. On the way down the windpipe, tiny hairs called cilia (say: SILL-ee-uh) move gently to keep mucus and dirt out of the lungs. The air then goes through the series of branches in your lungs, through the bronchi and the bronchioles. previous continue Thank You, Alveoli! The air finally ends up in the 600 million alveoli. As these millions of alveoli fill up with air, the lungs get bigger. Remember that experiment where you felt your lungs get larger? Well, you were really feeling the power of those awesome alveoli! It's the alveoli that allow oxygen from the air to pass into your blood. All the cells in the body need oxygen every minute of the day. Oxygen passes through the walls of each alveolus into the tiny capillaries that surround it. The oxygen enters the blood in the tiny capillaries, hitching a ride on red blood cells and traveling through layers of blood vessels to the heart.

The heart then sends the oxygenated (filled with oxygen) blood out to all the cells in the body. Waiting to Exhale When it's time to exhale (breathe out), everything happens in reverse: Now it's the diaphragm's turn to say, "Move it!" Your diaphragm relaxes and moves up, pushing air out of the lungs. Your rib muscles become relaxed, and your ribs move in again, creating a smaller space in your chest. By now your cells have used the oxygen they need, and your blood is carrying carbon dioxide and other wastes that must leave your body. The blood comes back through the capillaries and the wastes enter the alveoli. Then you breathe them out in the reverse order of how they came in — the air goes through the bronchioles, out the bronchi, out the trachea, and finally out through your mouth and nose. The air that you breathe out not only contains wastes and carbon dioxide, but it's warm, too! As air travels through your body, it picks up heat along the way. You can feel this heat by putting your hand in front of your mouth or nose as you breathe out.

What is the temperature of the air that comes out of your mouth or nose? With all this movement, you might be wondering why things don't get stuck as the lungs fill and empty! Luckily, your lungs are covered by two really slick special layers called pleural (say: PLOO-ral) membranes. These membranes are separated by a fluid that allows them to slide around easily while you inhale and exhale. previous continue Time for Talk Your lungs are important for breathing . . . and also for talking! Above the trachea (windpipe) is the larynx (say: LAIR-inks), which is sometimes called the voice box. Across the voice box are two tiny ridges called vocal cords, which open and close to make sounds. When you exhale air from the lungs, it comes through the trachea and larynx and reaches the vocal cords. If the vocal cords are closed and the air flows between them, the vocal cords vibrate and a sound is made. The amount of air you blow out from your lungs determines how loud a sound will be and how long you can make the sound.

Try inhaling very deeply and saying the names of all the kids in your class — how far can you get without taking the next breath? The next time you're outside, try shouting and see what happens — shouting requires lots of air, so you'll need to breathe in more frequently than you would if you were only saying the words. Experiment with different sounds and the air it takes to make them — when you giggle, you let out your breath in short bits, but when you burp , you let swallowed air in your stomach out in one long one! When you hiccup, it's because the diaphragm moves in a funny way that causes you to breathe in air suddenly, and that air hits your vocal cords when you're not ready. Love Your Lungs Your lungs are amazing. They allow you to breathe, talk to your friend, shout at a game, sing, laugh, cry, and more! And speaking of a game, your lungs even work with your brain to help you inhale and exhale a larger amount of air at a more rapid rate when you're running a mile — all without you even thinking about it once.

Keeping your lungs looking and feeling healthy is a smart idea, and the best way to keep your lungs pink and healthy is not to smoke. Smoking isn't good for any part of your body, and your lungs especially hate it. Cigarette smoke damages the cilia in the trachea so they can no longer move to keep dirt and other substances out of the lungs. Your alveoli get hurt too, because the chemicals in cigarette smoke can cause the walls of the delicate alveoli to break down, making it much harder to breathe. Finally, cigarette smoke can damage the cells of the lungs so much that the healthy cells go away, only to be replaced by cancer cells. Lungs are normally tough and strong, but when it comes to cigarettes, they can be hurt easily — and it's often very difficult or impossible to make them better. If you need to work with chemicals in an art or shop class, be sure to wear a protective mask to keep chemical fumes from entering your lungs. You can also show your love for your lungs by exercising! Exercise is good for every part of your body, and especially for your lungs and heart.

When you take part in vigorous exercise (like biking, running, or swimming, for example), your lungs require more air to give your cells the extra oxygen they need. As you breathe more deeply and take in more air, your lungs become stronger and better at supplying your body with the air it needs to succeed. Keep your lungs healthy and they will thank you for life! Lungs and Respiratory System Lungs and Respiratory System Breathing is so vital to life that it happens automatically. Each day, you breathe about 20,000 times, and by the time you're 70 years old, you'll have taken at least 600 million breaths. Respiratory System Basics All of this breathing couldn't happen without the respiratory system, which includes the nose, throat, voice box, windpipe, and lungs. At the top of the respiratory system, the nostrils (also called nares) act as the air intake, bringing air into the nose, where it's warmed and humidified. Tiny hairs called cilia protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air. Air can also be taken in through the mouth.

These two openings of the airway (the nasal cavity and the mouth) meet at the pharynx, or throat, at the back of the nose and mouth. The pharynx is part of the digestive system as well as the respiratory system because it carries both food and air. At the bottom of the pharynx, this pathway divides in two, one for food (the esophagus, which leads to the stomach) and the other for air. The epiglottis, a small flap of tissue, covers the air-only passage when we swallow, keeping food and liquid from going into the lungs. The larynx, or voice box, is the uppermost part of the air-only pipe. This short tube contains a pair of vocal cords, which vibrate to make sounds. The trachea, or windpipe, extends downward from the base of the larynx. It lies partly in the neck and partly in the chest cavity. The walls of the trachea are strengthened by stiff rings of cartilage to keep it open. The trachea is also lined with cilia, which sweep fluids and foreign particles out of the airway so that they stay out of the lungs.

At its bottom end, the trachea divides into left and right air tubes called bronchi, which connect to the lungs. Within the lungs, the bronchi branch into smaller bronchi and even smaller tubes called bronchioles. Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each lung houses about 300-400 million alveoli. The lungs also contain elastic tissues that allow them to inflate and deflate without losing shape and are encased by a thin lining called the pleura. This network of alveoli, bronchioles, and bronchi is known as the bronchial tree. The chest cavity, or thorax, is the airtight box that houses the bronchial tree, lungs, heart, and other structures. The top and sides of the thorax are formed by the ribs and attached muscles, and the bottom is formed by a large muscle called the diaphragm. The chest walls form a protective cage around the lungs and other contents of the chest cavity. Separating the chest from the abdomen, the diaphragm plays a lead role in breathing.

It moves downward when we breathe in, enlarging the chest cavity and pulling air in through the nose or mouth. When we breathe out, the diaphragm moves upward, forcing the chest cavity to get smaller and pushing the gases in the lungs up and out of the nose and mouth. continue Respiration The air we breathe is made up of several gases. Oxygen is the most important for keeping us alive because body cells need it for energy and growth. Without oxygen, the body's cells would die. Carbon dioxide is the waste gas produced when carbon is combined with oxygen as part of the energy-making processes of the body. The lungs and respiratory system allow oxygen in the air to be taken into the body, while also enabling the body to get rid of carbon dioxide in the air breathed out. Respiration is the set of events that results in the exchange of oxygen from the environment and carbon dioxide from the body's cells. The process of taking air into the lungs is inspiration, or inhalation, and the process of breathing it out is expiration, or exhalation. Air is inhaled through the mouth or through the nose.

Cilia lining the nose and other parts of the upper respiratory tract move back and forth, pushing foreign matter that comes in with air (like dust) either toward the nostrils to be expelled or toward the pharynx. The pharynx passes the foreign matter along to the stomach to eventually be eliminated by the body. As air is inhaled, the mucous membranes of the nose and mouth warm and humidify the air before it enters the lungs. When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward. In this way, the volume of the chest cavity is increased. Air pressure in the chest cavity and lungs is reduced, and because gas flows from high pressure to low, air from the environment flows through the nose or mouth into the lungs. In exhalation, the diaphragm moves upward and the chest wall muscles relax, causing the chest cavity to contract. Air pressure in the lungs rises, so air flows from the lungs and up and out of respiratory system through the nose or mouth. Every few seconds, with each inhalation, air fills a large portion of the millions of alveoli.

In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells. This oxygen-rich blood then flows back to the heart, which pumps it through the arteries to oxygen-hungry tissues throughout the body. In the tiny capillaries of the body tissues, oxygen is freed from the hemoglobin and moves into the cells. Carbon dioxide, which is produced during the process of diffusion, moves out of these cells into the capillaries, where most of it is dissolved in the plasma of the blood. Blood rich in carbon dioxide then returns to the heart via the veins. From the heart, this blood is pumped to the lungs, where carbon dioxide passes into the alveoli to be exhaled. previous continue Lungs & Respiratory System Problems The respiratory system is susceptible to a number of diseases, and the lungs are prone to a wide range of disorders caused by pollutants in the air. The most common problems of the respiratory system are: Asthma . More than 20 million people in the United States have asthma, and it's the #1 reason that kids frequently miss school.

Asthma is a chronic inflammatory lung disease that causes airways to tighten and narrow. Often triggered by irritants in the air such as cigarette smoke, asthma flares involve contraction of the muscles and swelling of the lining of the tiny airways. The resulting narrowing of the airways prevents air from flowing properly, causing wheezing and difficulty breathing, sometimes to the point of being life-threatening. Controlling asthma starts with an asthma management plan , which usually involves avoiding asthma triggers and, sometimes, taking medicines. Bronchiolitis . Not to be confused with bronchitis, bronchiolitis is an inflammation of the bronchioles, the smallest branches of the bronchial tree. Bronchiolitis affects mostly infants and young children, and can cause wheezing and serious difficulty breathing. It's usually caused by specific viruses in the wintertime, including respiratory syncytial virus (RSV) . Chronic obstructive pulmonary disease (COPD). COPD is a term that describes two lung diseases — emphysema and chronic bronchitis: Long-term smoking often causes emphysema, and although it seldom affects kids and teens, it can have its roots in the teen and childhood years.

Talking to your kids about smoking is a key part of preventing smoking-related diseases. In emphysema, the lungs produce an excessive amount of mucus and the alveoli become damaged. It becomes difficult to breathe and get enough oxygen into the blood. In bronchitis, a common disease of adults and teens, the membranes lining the larger bronchial tubes become inflamed and an excessive amount of mucus is produced. The person develops a bad cough to get rid of the mucus. Cigarette smoking is a major cause of chronic bronchitis in teens. previous continue Other Conditions Common cold . Caused by more than 200 different viruses that cause inflammation in the upper respiratory tract, the common cold is the most common respiratory infection. Symptoms may include a mild fever, cough, headache, runny nose, sneezing, and sore throat. Cough . A cough is a symptom of an illness, not an illness itself. There are many different types of cough and many different causes, ranging from not-so-serious to life-threatening. Some of the more common causes affecting kids are the common cold, asthma, sinusitis, seasonal allergies, croup, and pneumonia.

Among the most serious causes of cough are tuberculosis (TB) and whooping cough (pertussis) . Cystic fibrosis (CF) . Affecting more than 30,000 kids and young adults in the United States, cystic fibrosis is the most common inherited disease affecting the lungs. Affecting primarily the respiratory and digestive systems, CF causes mucus in the body to be abnormally thick and sticky. The mucus can clog the airways in the lungs and make a person more vulnerable to bacterial infections. Lung cancer. Caused by an abnormal growth of cells in the lungs, lung cancer is a leading cause of death in the United States and is usually caused by smoking cigarettes. It starts in the lining of the bronchi and takes a long time to develop, so it's usually a disease in adults. Symptoms include a lasting cough that may bring up blood, chest pain, hoarseness, and shortness of breath. Radon gas (a gas that occurs in soil and rocks) exposure also might cause lung cancer. Radon is more likely to happen in certain parts of the United States.

You can check your home's radon level with a radon kit available at your local home supply or hardware store. Pneumonia . This inflammation of the lungs usually happens because of bacterial or viral infection. Pneumonia causes fever and inflammation of lung tissue, and makes breathing difficult because the lungs have to work harder to transfer oxygen into the bloodstream and remove carbon dioxide from the blood. Common causes of pneumonia are influenza (the flu) and infection with the bacterium Streptococcus pneumoniae. Pulmonary hypertension. This is when the blood pressure in the arteries of the lungs is abnormally high, which means the heart has to work harder to pump blood against that high pressure. Pulmonary hypertension may happen in children because of a congenital (present at birth) heart defect or because of a health condition such as HIV infection . previous continue Respiratory Diseases of Newborns Several respiratory conditions can affect a newborn baby just starting to breathe for the first time. Premature babies are at increased risk for conditions such as: Respiratory distress syndrome of the newborn. Babies born prematurely may not have enough surfactant in the lungs.

Surfactant helps to keep the baby's alveoli open; without surfactant, the lungs collapse and the baby is unable to breathe. Apnea of prematurity (AOP) . Apnea is a medical term that means someone has stopped breathing. Apnea of prematurity (AOP) is a condition in which premature infants stop breathing for 15 to 20 seconds during sleep. AOP usually happens 2 days to 1 week after a baby is born. The lower the infant's weight and level of prematurity at birth, the more likely the baby is to have AOP spells. Bronchopulmonary dysplasia (BPD) . BPD involves abnormal development of lung tissue. Sometimes called chronic lung disease, or CLD, it's a disease in infants characterized by inflammation and scarring in the lungs. It develops most often in premature babies who are born with underdeveloped lungs. Meconium aspiration . Meconium aspiration is when a newborn inhales (aspirates) a mixture of meconium (baby's first feces, ordinarily passed after birth) and amniotic fluid during labor and delivery.

The inhaled meconium can cause a partial or complete blockage of the baby's airways. Persistent pulmonary hypertension of the newborn (PPHN). In the uterus, a baby's circulation bypasses the lungs. Normally, when a baby is born and begins to breathe air, his or her body quickly adapts and begins the process of respiration. PPHN is when a baby's body doesn't make that transition from fetal circulation to newborn circulation. This condition can cause symptoms such as rapid breathing, rapid heart rate, respiratory distress, and cyanosis (blue-tinged skin). Transient tachypnea of the newborn (TTN) . Rapid breathing in a full-term newborn (more than 60 breaths a minute) is called transient tachypnea. Although some respiratory diseases can't be prevented, many chronic lung and respiratory illnesses can be prevented by avoiding smoking, staying away from pollutants and irritants, washing hands often to avoid infection, and getting regular medical checkups.

Question: Pulmonary relates to which part of the human body?
Answer: Lungs